Okhlopkov Kirill I, Zilli Attilio, Tognazzi Andrea, Rocco Davide, Fagiani Luca, Mafakheri Erfan, Bollani Monica, Finazzi Marco, Celebrano Michele, Shcherbakov Maxim R, De Angelis Costantino, Fedyanin Andrey A
Faculty of Physics, Lomonosov Moscow State University, 119991 Moscow, Russia.
Department of Physics, Politecnico di Milano, Piazza Leonardo Da Vinci 32, 20133 Milano, Italy.
Nano Lett. 2021 Dec 22;21(24):10438-10445. doi: 10.1021/acs.nanolett.1c03790. Epub 2021 Dec 7.
Metasurfaces are versatile tools for manipulating light; however, they have received little attention as devices for the efficient control of nonlinearly diffracted light. Here, we demonstrate nonlinear wavefront control through third-harmonic generation (THG) beaming into diffraction orders with efficiency tuned by excitation of hybrid Mie-quasi-bound states in the continuum (BIC) modes in a silicon metasurface. Simultaneous excitation of the high-Q collective Mie-type modes and quasi-BIC modes leads to their hybridization and results in a local electric field redistribution. We probe the hybrid mode by measuring far-field patterns of THG and observe the strong switching between (0,-1) and (-1,0) THG diffraction orders from 1:6 for off-resonant excitation to 129:1 for the hybrid mode excitation, showing tremendous contrast in controlling the nonlinear diffraction patterns. Our results pave the way to the realization of metasurfaces for novel light sources, telecommunications, and quantum photonics.
超表面是用于操纵光的多功能工具；然而，作为有效控制非线性衍射光的器件，它们很少受到关注。在这里，我们展示了通过三倍频产生（THG）实现的非线性波前控制，通过激发硅超表面中连续谱中的混合米氏准束缚态（BIC）模式来调节效率，使THG光束进入衍射级次。高Q值的集体米氏型模式和准BIC模式的同时激发导致它们的杂化，并导致局部电场重新分布。我们通过测量THG的远场图案来探测混合模式，并观察到从非共振激发时（0，-1）和（-1，0）THG衍射级次的1:6到混合模式激发时的129:1的强烈切换，这表明在控制非线性衍射图案方面有巨大的对比度。我们的结果为实现用于新型光源、电信和量子光子学的超表面铺平了道路。
